A digital camera is a component often included in commercial electronic media device platforms. Digital cameras are now available in wearable form factors (e.g., video capture earpieces, video capture headsets, video capture eyeglasses, etc.), as well as embedded within smartphones, tablet computers, and notebook computers, etc. Three-dimensional (3D) cameras are becoming more common, and can now be found on many mobile devices/platforms, including vehicles. These devices provide enhanced entertainment and utility experiences to an end user. For example, photography and vehicle control systems may be enhanced by depth (i.e., range) information output from the 3D camera. Existing technology to generate 3D camera images include stereo or multi-cameras, structured light systems comprising projected light patterns and cameras, time-of-flight (TOF) cameras, etc.
An important application enabled by 3D cameras is point-to-point measurement where the distance between two points on an image that are typically specified by the user, is measured in real world units, such as centimeters, etc. The simplest way to measure such a point-to-point distance is to utilize the range information, along with geometric calibration information, to compute 3D coordinates of the measurement points. Measurement of the intervening distance between the selected measurement points can then be computed. Such an approach to measurement suffers from several drawbacks, however. For example, range values are often noisy, introducing significant error when a pair of points are specified. Also, the technique is also susceptible to imprecise user input of the measurement location.
A more robust point-to-point distance measurement in 3D camera images is therefore advantageous.